ETA: It didn't come up for me when I first answered this question, but we would also do well to consider how we are raising our boys, the examples of male dominance and bravado they receive growing up, how we can engage them to be communicative about their feelings with us as parents, how we can take the stress of having to constantly prove their 'manliness' off our teens, etc and teach them to have healthy relationships while being their authentic selves. I think this is more to the crux of the problem than just media. When boys don't feel they have options for dealing with their emotions and challenges, sad things can happen.
First, I think you are being *very* assumptive when you say "nobody cares" about this topic. There are very many careful parents (some on this site) who choose not to expose their children to those violent movies, tv, games and other media which is inappropriate for a growing kid.
You are making an assumption that every parent in your audience has not only signed off on buying/allowing their kids to see/experience violence, but also doesn't care about the affect this has had on their children.
There have been plenty of parents who have addressed this in their own homes. If you want to address this further, start with the FTC. They're the agency that was gutted and deregulated during the past few decades. It used to be that these sorts of games and media and toys were not allowed to be advertised to children.
In our family's case, we have had to address death far earlier than we wanted to. When my son was four, a fellow preschooler's baby brother died, likely of SIDS. This was a sad introduction to death, however, we have handled it as compassionately and appropriately as we could have. A year and a half later and we are now only addressing the current shootings if they come up.
I don't fear telling my son about the shootings, if it does come up. We don't watch much tv during the daytime (usually never) and have had the radio off. (However, why give my sweet boy something to worry about if it hasn't fallen into his lap? He's a kindergartener himself. )We don't 'do' violent stories or media--he has told us he isn't ready for it yet, and we respect his comfort level. Yet, my son will still create violent play scenarios from his imagination. Here's a link to a good article by Bruno Bettelheim which explains the 'why' of this and why it is so common (and why it is linked to working through/mastering internal conflict):
http://www.theatlantic.com/magazine/archive/1987/03/the-i...
So, if you can't tell-- I do think about it. Yes, it is still there. However, I can't stick my kid in a bubble. He's going to *hear* about ninjas, Star Wars and Superheroes from friends at school. This is what they like to play. My best response is not to demonize this, but to explain that it's pretend, that real violence does hurt people, to not expose him to anything I don't think he can reasonably handle, and to continue to teach peace, positive problem-solving skills and empathy on a daily basis as real-life challenges arise.
I guess you struck a nerve with me because I'm not the only parent who cares deeply about this. I grew up in a violent home and have worked very, very hard for years to ensure that my son will not have to suffer the same upbringing. So assuming that all the parents are turning a blind eye and then acting horrified is pretty far from the truth. I haven't read any of the other comments, but I'm pretty sure that there are other parents who feel this way.
If you want more resources, try Campaign for a Commercial-Free Childhood, Empowered by Play, or TRUCE (Teachers Resisting Unhealthy Children's Entertainment). No one talks much about these entities, but they are on the front lines of fighting for children's social and emotional health and safety. These groups don't have the big money. Go complain to Disney for the violence and sexism in nearly every movie I've seen them make in the last 20+ years or earlier. (I may not be current with this as I don't get a kick out of Disney movies in general.) Or just do what I do-- very carefully pick and choose what your children watch and when. That is ALL I can do.